The two lives of Cherie Blair

The piqued response of the nation's headline writers to Cherie Blair's forthcoming autobiography tells – perhaps better than the book itself ever will – the real story. The one of how a prime minister's wife preceded her husband into unpopularity.

Mrs Blair, who turns 53 today, is promising a "full account" of her rise from a troubled working-class childhood in the North-West to become Downing Street chatelaine, but for all the allure of the storyline and the remarkableness of the woman at its core, the proposed book is already being panned as an exercise in greed, vanity, and the pawning of principles to pay off a £5 million mortgage.

Even Cherie's decision to proceed without the services of a ghostwriter is taken as evidence of an overweening belief in her own abilities, an inability to place trust in others, and, perhaps most damagingly, a steely determination to pocket all the proceeds for herself.

Yet there's an irony in the scepticism, for those who are harshest on Cherie also tend to be those most insistent on knowing more about her. The argument goes that she was no ordinary prime minister's wife, but a secretive and largely unaccountable political force in her own right, and those who make it may have a point, for very little of what Mrs Blair actually did, said or thought in Number 10 has ever been revealed. She gave no interviews of consequence, disliked being photographed without stylists and hairdressers on hand, and treated all who sought to inquire into her life with implacable hostility.

Linda McDougall, a TV producer and wife of the Labour MP Austin Mitchell, who wrote an unauthorised biography of Cherie, recalls: "When I set out on my book, I thought it would be a wonderful story of how, in modern Britain, even the humblest could make it to the top. I wrote to Cherie several times asking for her cooperation. She never replied. I was then told that not only did she not want her biography written, she would advise her friends not to cooperate with me either. And she was true to her word. She absolutely hated it. Every door was sealed."

For most of Cherie's early years in Downing Street, this defensive approach served her well. Such attention as she attracted tended to focus on her admirable efforts to raise four children while maintaining a high-powered career as a barrister, and a semi-official position in public life.

Women, especially, were invited to regard her as a role-model, and even though many of them regarded her as humourless, stuck-up, and sadly typical of New Labour, Cherie's determined refusal to put her life on show only made her seem more interesting.

She was packaged as a new kind of political wife; one whose role uncannily mirrored that of Hillary Clinton, then in the White House with her husband Bill. Like Hillary she got her comeuppance swiftly.

Things began to go wrong four years ago when listeners to the Radio Four Today programme voted her the person they would most like to have deported. Vigorous competition had come in the shape of suspected terrorists, errant royals, and annoying starlets, but Cherie's reported forays into dodgy finance and occult healing techniques turned the audience decisively against her.

She had developed a friendship with – more accurately a dependency upon – Carole Caplin, an ex-glamour model turned "lifestyle guru" whose boyfriend at the time was Peter Foster, a convicted Australian fraudster.

For all the "I'm no Superwoman", apologies that followed, and the undoubted good works that Mrs Blair has done, the taint of "Cheriegate" has never left her.

Now, for a rumoured £1 million, she is throwing those sealed doors open. What might we find inside? Almost everything that matters about Mrs Blair leads to the place she least likes the uninvited to go – back to her strange, troubled childhood.

She was born on September 23, 1954, the daughter of Tony Booth – a rising young actor from Liverpool with an eye for the girls and a strong thirst. Tony would eventually become famous as the idle "Scouse git" in the classic BBC TV comedy Till Death Us Do Part, but when he met 18-year-old actress Gale Howard, he was 21, newly released from national service and touring with a tiny theatrical company in Yorkshire.

The pregnancy was an accident. Nevertheless, the young lovers – as they tended to do in those days – married before Cherie's birth. They had no money and Tony recalls that both he and Gale were desperate to make it in show business.

To work, though, they had to travel, and having travelled they had to accept the unsocial hours demanded of actors. Cherie was left behind to be raised by Tony's mother in a house on a Liverpool back street.

Tony, as he admits in his own autobiography, was not only an absent father, but a hopelessly unfaithful husband. He had a string of affairs, and while working on and off in London's West End fell in love with another actress who also became pregnant by him. An acrimonious divorce from Gale followed, and it would be several years before Cherie saw her father again.

Cherie's upbringing was, perhaps, not as deprived as it is sometimes made out to be. Certainly she was at the heart of a large, close, resoundingly working class and devoutly Roman Catholic family, which always did its best for her.

She had friends, trips and was always beautifully turned out. The first hint that there might be anything special about her came when she went to Seafield convent school at 11. "Once or twice in a professional lifetime," said her old headmistress later, "might you come across a truly, exceptionally clever child. Cherie was one of those."

Upon leaving school, she studied law at the LSE, going on to gain the highest bar examination marks of any student in the country in her year, then, in the mid-1970s, she joined a powerful London chambers headed by Derry Irvine, who later became Lord Chancellor. There she met Tony Blair.

They seemed an odd couple from the start. He was an affable, easy-going, ex-public schoolboy who liked pop music and, for a while, sported a heavy metal haircut. His ideological sympathies, in so far as he ever expressed them, were broadly conservative.

Cherie changed all that. From the back streets of down-on-its-luck Liverpool she brought a strong sense of social justice that manifested itself as a hunger for political power. Within a year she had radicalised Blair, and set him on the road – one he had never previously dreamed of travelling – to 10 Downing Street.

In 1983, Tony and Cherie both stood for Parliament as Labour candidates. He won, she lost. It was a fundamental power shift that has defined their relationship ever since.

There are, in reality, two Cheries; the hyper-smart lawyer and the little girl lost, the supportive wife and the public liability, the modern woman with the social conscience and the one that needs money fast.

They even have different names – Cherie Blair and Cherie Booth. One autobiography may not be enough for both of them.